SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe842a3be31d7697aff3edfcdb0b46f523980a6c2981e7604b397da2bd3acad9' 
  AND token = '0Swa1GsEY1btLZOvkf0PPRFl1QHbQPzsBu9VUI87pb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}